I'm putting in a shower/tub unit and we want to have the tub spout on the side of the tub in the middle. The valve unit will be in the usual place on the end of the tub, with the shower head above it. The diverter is in the tub spout. Will this work, or would it screw up the diverter if we put it on the side?

Personally I’d put the knobs on the middle of the side with the spout, just put the shower head on the end as usual. I’ve actually seen this done recently in a model home— what I don’t know is if all diverted valves are created alike, and if this works with any of them.
– TysonMar 27 '18 at 2:31

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Is there a functional reason to put the tub spout on the long wall? It seems to me that it would be an obstruction to leg movement. I am especially aware of this since I am aging, but I think it could apply to younger people as well.
– Jim StewartMar 27 '18 at 11:25

The purpose is so two people can take a bath together, and one doesn't have the spout in their back. I put in one a while ago, but it had the diverter in the valve mechanism.
– KenMar 27 '18 at 14:20

The wall is open and there is no issue with wiring. As far as the work goes, it's not all that much. The directions say the spout should be directly under the valve, between 8 and 18 inches down, with no more than one elbow. I'm just not sure if changing the placement would screw up the diversion of the water.
– KenMar 27 '18 at 14:25

The extra length and two to four 90 deg turns might well cause water to come out the shower head when it is meant to come out the tub spout. This could be stopped by putting a shut-off valve just behind the shower head. signaturehardware.com/…
– Jim StewartMar 27 '18 at 17:11

2 Answers
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A normal tub diverter valve works because when the tub spout is open, it requires less force for the water to come out of the spout than it does for water to get pushed up to the shower head. The water takes the path of least resistance. When the tub spout diverter is closed, the water is naturally forced up the pipe to the shower head.

The reason the instructions say to only use one elbow and to limit the distance is to reduce the resistance of the water flowing out of the spout. If the plumbing to the spout is too complex and provides too much resistance, you could have some water get pushed up to the shower head no matter what.

So, this plan might work, or there might just be too much resistance in the pipe snaking around the tub to the other side. It's hard to say for sure. If the valve is installed lower, I think you chances are better. Also the tub spout pipe will have to go around the tub and not over it because water would certainly flow out of the head all the time if you did that. Try to use only 3-4 fittings on the pipe - don't make any extra bends.

I looked around a little and found this forum post where a plumber used PEX pipe and three elbows even with the tub spout on the same side. That was enough to make water dribble out of the shower head. PEX could have made this problem worse because the fittings don't have a full 1/2" inside diameter so they restrict flow more than copper would. Still, doesn't look good for your plan since you'd also have a minimum of 3 elbows (with PEX, 4 elbows using copper).

From a plumbing standpoint it might work, but it would be very unusual. The water pipe would have to go through a number of studs. What functionality would this give you?

Also there can be electrical wiring in the long wall of the tub (to serve receptacles on the other side of the wall from the tub). It may not be best practice to have wiring in the vicinity of water pipes for a tub/shower, at least copper pipes.

I could also see issues of insulation and working around this. I assume the walls are open and you can see studs and such? Otherwise it would like a lot of cutting. The approach you are going for would require 2 pipes, one to the spout/diverter and one to the shower head. If you could move all the plumbing to the center wall, then you could run 1 pipe from the spout/diverter to the shower head, and even if you wanted, run another to the opposite side and install a second shower head. 2 people could shower together, or you could have water from both sides.
– Jeff CatesMar 27 '18 at 13:25

Is this an extra large tub? If not, there is just enough room for one person!
– Jim StewartMar 27 '18 at 18:27

They didn't specify the tub size, however, for a shower, you can easily get 2 people in a standard tub.
– Jeff CatesMar 28 '18 at 18:45